Quantitative EPRThere is a growing need in both industrial and academic research to obtain accurate quantitative results from continuous wave (CW) electron paramagnetic resonance (EPR) experiments. This book describes various sample-related, instrument-related and software-related aspects of obtaining quantitative results from EPR expe- ments. Some speci?c items to be discussed include: selection of a reference standard, resonator considerations (Q, B ,B ), power saturation, sample position- 1 m ing, and ?nally, the blending of all the factors together to provide a calculation model for obtaining an accurate spin concentration of a sample. This book might, at ?rst glance, appear to be a step back from some of the more advanced pulsed methods discussed in recent EPR texts, but actually quantitative “routine CW EPR” is a challenging technique, and requires a thorough understa- ing of the spectrometer and the spin system. Quantitation of CW EPR can be subdivided into two main categories: (1) intensity and (2) magnetic ?eld/mic- wave frequency measurement. Intensity is important for spin counting. Both re- tive intensity quantitation of EPR samples and their absolute spin concentration of samples are often of interest. This information is important for kinetics, mechanism elucidation, and commercial applications where EPR serves as a detection system for free radicals produced in an industrial process. It is also important for the study of magnetic properties. Magnetic ?eld/microwave frequency is important for g and nuclear hyper?ne coupling measurements that re?ect the electronic structure of the radicals or metal ions. |
Contents
| 1 | |
Chapter 2 Why Should Measurements Be Quantitative? | 15 |
Chapter 3 Important Principles for Quantitative EPR | 25 |
Chapter 4 A More in Depth Look at the EPR Signal Response | 37 |
Chapter 5 Practical Advice About Crucial Parameters | 63 |
Chapter 6 A Deeper Look at B1B1 and Modulation Field Distribution in a Resonator | 68 |
Chapter 7 Resonator Q | 79 |
Chapter 8 Filling Factor | 89 |
Other editions - View all
Quantitative EPR Gareth R. Eaton,Sandra S. Eaton,David P. Barr,Ralph T. Weber No preview available - 2010 |
Quantitative EPR Gareth R. Eaton,Sandra S. Eaton,David P. Barr,Ralph T. Weber No preview available - 2010 |
Quantitative EPR Gareth R. Eaton,Sandra S. Eaton,David P. Barr,Ralph T. Weber No preview available - 2014 |
Common terms and phrases
1/f noise absorption signal accurate baseline broadening Bruker calculation calibration cavity resonator Chem constant cryostat CW EPR data points Demodulated depends detector current Dewar dielectric double integration DPPH Eaton and Eaton effect electron paramagnetic resonance electron spin resonance energy EPR absorption EPR line EPR signal EPR spectrometer EPR spectrum example experimental field scan filling factor filter free radical g-factor hyperfine coupling hyperfine splitting increases kHz modulation line shape line width linear Lorentzian Magn magnetic field Mazu´r measurement metal microwave frequency microwave power Mn(II modulation amplitude modulation frequency Nagy nitroxide noise figure number of spins optimal output parameters peak peak-to-peak phase sensitive detection power levels power saturation curve pulse quantitative EPR ratio receiver gain reference standard relaxation resonator Q Rinard sample tube signal amplitude signal channel signal intensity solvent species spectra sweep width TE102 cavity temperature Tempol transition values weak pitch X-band Xepr Yordanov